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3d458a81 AW |
1 | /* An fseeko() function that, together with fflush(), is POSIX compliant. |
2 | Copyright (C) 2007-2011 Free Software Foundation, Inc. | |
3 | ||
4 | This program is free software; you can redistribute it and/or modify | |
5 | it under the terms of the GNU Lesser General Public License as published by | |
6 | the Free Software Foundation; either version 2, or (at your option) | |
7 | any later version. | |
8 | ||
9 | This program is distributed in the hope that it will be useful, | |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | GNU Lesser General Public License for more details. | |
13 | ||
14 | You should have received a copy of the GNU Lesser General Public License along | |
15 | with this program; if not, write to the Free Software Foundation, | |
16 | Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ | |
17 | ||
18 | #include <config.h> | |
19 | ||
20 | /* Specification. */ | |
21 | #include <stdio.h> | |
22 | ||
23 | /* Get off_t and lseek. */ | |
24 | #include <unistd.h> | |
25 | ||
26 | #include "stdio-impl.h" | |
27 | ||
28 | int | |
29 | fseeko (FILE *fp, off_t offset, int whence) | |
30 | #undef fseeko | |
31 | #if !HAVE_FSEEKO | |
32 | # undef fseek | |
33 | # define fseeko fseek | |
34 | #endif | |
35 | { | |
36 | #if LSEEK_PIPE_BROKEN | |
37 | /* mingw gives bogus answers rather than failure on non-seekable files. */ | |
38 | if (lseek (fileno (fp), 0, SEEK_CUR) == -1) | |
39 | return EOF; | |
40 | #endif | |
41 | ||
42 | /* These tests are based on fpurge.c. */ | |
43 | #if defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */ | |
44 | if (fp->_IO_read_end == fp->_IO_read_ptr | |
45 | && fp->_IO_write_ptr == fp->_IO_write_base | |
46 | && fp->_IO_save_base == NULL) | |
47 | #elif defined __sferror || defined __DragonFly__ /* FreeBSD, NetBSD, OpenBSD, DragonFly, MacOS X, Cygwin */ | |
48 | # if defined __SL64 && defined __SCLE /* Cygwin */ | |
49 | if ((fp->_flags & __SL64) == 0) | |
50 | { | |
51 | /* Cygwin 1.5.0 through 1.5.24 failed to open stdin in 64-bit | |
52 | mode; but has an fseeko that requires 64-bit mode. */ | |
53 | FILE *tmp = fopen ("/dev/null", "r"); | |
54 | if (!tmp) | |
55 | return -1; | |
56 | fp->_flags |= __SL64; | |
57 | fp->_seek64 = tmp->_seek64; | |
58 | fclose (tmp); | |
59 | } | |
60 | # endif | |
61 | if (fp_->_p == fp_->_bf._base | |
62 | && fp_->_r == 0 | |
63 | && fp_->_w == ((fp_->_flags & (__SLBF | __SNBF | __SRD)) == 0 /* fully buffered and not currently reading? */ | |
64 | ? fp_->_bf._size | |
65 | : 0) | |
66 | && fp_ub._base == NULL) | |
67 | #elif defined __EMX__ /* emx+gcc */ | |
68 | if (fp->_ptr == fp->_buffer | |
69 | && fp->_rcount == 0 | |
70 | && fp->_wcount == 0 | |
71 | && fp->_ungetc_count == 0) | |
72 | #elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, mingw, NonStop Kernel */ | |
73 | if (fp_->_ptr == fp_->_base | |
74 | && (fp_->_ptr == NULL || fp_->_cnt == 0)) | |
75 | #elif defined __UCLIBC__ /* uClibc */ | |
76 | if (((fp->__modeflags & __FLAG_WRITING) == 0 | |
77 | || fp->__bufpos == fp->__bufstart) | |
78 | && ((fp->__modeflags & (__FLAG_READONLY | __FLAG_READING)) == 0 | |
79 | || fp->__bufpos == fp->__bufread)) | |
80 | #elif defined __QNX__ /* QNX */ | |
81 | if ((fp->_Mode & 0x2000 /* _MWRITE */ ? fp->_Next == fp->_Buf : fp->_Next == fp->_Rend) | |
82 | && fp->_Rback == fp->_Back + sizeof (fp->_Back) | |
83 | && fp->_Rsave == NULL) | |
84 | #elif defined __MINT__ /* Atari FreeMiNT */ | |
85 | if (fp->__bufp == fp->__buffer | |
86 | && fp->__get_limit == fp->__bufp | |
87 | && fp->__put_limit == fp->__bufp | |
88 | && !fp->__pushed_back) | |
89 | #else | |
90 | #error "Please port gnulib fseeko.c to your platform! Look at the code in fpurge.c, then report this to bug-gnulib." | |
91 | #endif | |
92 | { | |
93 | /* We get here when an fflush() call immediately preceded this one. We | |
94 | know there are no buffers. | |
95 | POSIX requires us to modify the file descriptor's position. | |
96 | But we cannot position beyond end of file here. */ | |
97 | off_t pos = | |
98 | lseek (fileno (fp), | |
99 | whence == SEEK_END && offset > 0 ? 0 : offset, | |
100 | whence); | |
101 | if (pos == -1) | |
102 | { | |
103 | #if defined __sferror || defined __DragonFly__ /* FreeBSD, NetBSD, OpenBSD, DragonFly, MacOS X, Cygwin */ | |
104 | fp_->_flags &= ~__SOFF; | |
105 | #endif | |
106 | return -1; | |
107 | } | |
108 | ||
109 | #if defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */ | |
110 | fp->_flags &= ~_IO_EOF_SEEN; | |
111 | #elif defined __sferror || defined __DragonFly__ /* FreeBSD, NetBSD, OpenBSD, DragonFly, MacOS X, Cygwin */ | |
112 | # if defined __CYGWIN__ | |
113 | /* fp_->_offset is typed as an integer. */ | |
114 | fp_->_offset = pos; | |
115 | # else | |
116 | /* fp_->_offset is an fpos_t. */ | |
117 | { | |
118 | /* Use a union, since on NetBSD, the compilation flags | |
119 | determine whether fpos_t is typedef'd to off_t or a struct | |
120 | containing a single off_t member. */ | |
121 | union | |
122 | { | |
123 | fpos_t f; | |
124 | off_t o; | |
125 | } u; | |
126 | u.o = pos; | |
127 | fp_->_offset = u.f; | |
128 | } | |
129 | # endif | |
130 | fp_->_flags |= __SOFF; | |
131 | fp_->_flags &= ~__SEOF; | |
132 | #elif defined __EMX__ /* emx+gcc */ | |
133 | fp->_flags &= ~_IOEOF; | |
134 | #elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, mingw, NonStop Kernel */ | |
135 | fp->_flag &= ~_IOEOF; | |
136 | #elif defined __MINT__ /* Atari FreeMiNT */ | |
137 | fp->__offset = pos; | |
138 | fp->__eof = 0; | |
139 | #endif | |
140 | /* If we were not requested to position beyond end of file, we're | |
141 | done. */ | |
142 | if (!(whence == SEEK_END && offset > 0)) | |
143 | return 0; | |
144 | } | |
145 | return fseeko (fp, offset, whence); | |
146 | } |